Organic NLO compositions have been developed to influence the direction, frequency, amplitude, and phase of light. Typical organic NLO compositions contain a polymeric composition having polar NLO molecules incorporated therein. Typical polar NLO molecules have electron donor and acceptor groups linked by conjugated .pi.-electron systems. When light is passed through the NLO compositions, the incorporated polar molecules generate a NLO response. Polar NLO molecules have been incorporated into polymeric compositions using one of two distinct methods.
In a first method, the polar NLO molecules are dissolved in a polymeric composition. The polar NLO molecules are referred to as "guests", and the polymeric composition is referred to as a "host". In such "guest-host" compositions, the NLO guest molecules are dispersed in the polymeric host without being bonded thereto to form a polymeric NLO composition. Guest-host polymeric NLO compositions are disclosed, for example, in EP-A-0,218,938 and U.S. Pat. No. 4,707,303.
In a second method, the polar NLO molecules are incorporated into a polymeric composition by covalently attaching the former to a polymer. An example of a polymer having NLO groups covalently bonded thereto is disclosed in U.S. Pat. No. 5,006,729.
Whether polar NLO molecules are incorporated into a polymeric composition by dispersing or bonding, the molecules need to be aligned to achieve a NLO response. It is known that NLO compositions can display a second-order response when the .chi..sup.(2) (chi squared) optically-responsive molecules are aligned noncentrosymmetrically. Noncentrosymmetric means that inversion symmetry is not present in the composition. Noncentrosymmetric molecular alignment has been accomplished by heating the polymeric composition to its glass transition temperature (T.sub.g), applying a DC electric field across the polymeric composition to cause the incorporated NLO molecules to line up in the direction of the applied field (referred to as "poling"), and cooling the polymeric composition below T.sub.g while the electric field is still being applied.
The following publications provide general background information on NLO materials: R. Dagani, "Chemists Crucial to Progress in Nonlinear Optical Materials", Chem. & Eng News 21-25 (Jun. 11, 1990); S. Tripathy et al., "Nonlinear Optics and Organic Materials", Chemtech 747-752 (December 1989); and D. S. Chemla and J. Zyss, "Nonlinear Optical Properties of Organic Molecules and Crystals", vols. I & II,, ch II-7 and II-8 Academic Press, N.Y. (1987).
U.S. Pat. Nos. 3,932,526, 3,933,914, 3,984,357, 4,018,810, 4,069,233, 4,156,696, and 4,357,405 disclose PDFMs and processes for preparing those PDFMs. The PDFMs are disclosed to be useful as catalysts, dyes, and sensitizers. These patents do not teach or suggest that PDFMs will provide second-order NLO effects when aligned noncentrosymmetrically in a polymeric composition.
I. I. Malentina et al., Inst. Org. Chem., Acad. Sci. Ukrainian SSR, Plenum Publishing (1980) (translated from Zhurnal Organicheskoi Khimii, v. 15, n. 11, pp. 2416-17 (November 1979)) discloses preparing a disulfonyl fluoride, p-(CH.sub.3).sub.2 NC.sub.6 H.sub.4 CH.dbd.C(SO.sub.2 F).sub.2, from methane disulfonyl fluoride and 4-dimethylaminobenzaldehyde. No utility for the disulfonyl fluoride is disclosed.
U.S. Pat. No. 4,973,429 discloses organic compositions having NLO properties. The organic compositions are in the form of a film and contain compounds of the formula: ##STR1## where X is .dbd.CH-- or .dbd.N--, R.sup.1 is C.sub.12 -C.sub.30 -alkyl, R.sup.2 is hydrogen or C.sub.1 -C.sub.30 -alkyl, R.sup.3 is --NO.sub.2, --CN, --CF.sub.3, --COCF.sub.3, --SO.sub.2 CH.sub.3 or --SO.sub.2 CF.sub.3, R.sup.4 is hydrogen or is defined in the same way as R.sup.3, R.sup.5 , hydrogen or --NR.sup.6 R.sup.7 and R.sup.6 and R.sup.7 independently of one another are hydrogen or C.sub.1 -C.sub.30 -alkyl, it also being possible for any of the alkyl radicals to be partially fluorinated or perfluorinated.
U.S. Pat. No. 5,006,729 discloses a NLO compound comprising an electron donor group linked to an electron acceptor group by a .pi.-conjugated group. The electron acceptor is a sulfone group containing a substituent selected from the group consisting of alkyl, hydroxyalkyl, and alkyl(meth-)acrylate moieties. The sulfone group is represented by the formula: ##STR2## where D is the electron donor group, .pi. represents the conjugated group, and R.sub.1 is one of the noted substituents.
The use of D, R.sub.1, and R.sup.1 -R.sup.7 above to describe the compounds disclosed in U.S. Pat. Nos. 4,973,429 and 5,006,729 is not to be confused with the use of similar notation below to describe the present invention.